The present invention relates to a curable resin and a composition containing the same, and more particularly to a curable resin whose main chain consists essentially of an aliphatic polyester chain and which has on the polymer chain end at least two hydrolyzable silyl groups, and the composition containing the same.
The present invention provides a curable resin which is excellent in flexibility, solvent resistance, resistance to acid rain (acid rain resistance), resistance to scratch (scratch resistance), and is low in viscosity, and a composition containing the above-mentioned resin. The curable resin of the present invention is suitable for use as a base resin used in coatings, adhesives, sealing agents and potting agents, or as a polymer to be blended with a cellulose such as nitrocellulose or cellulose acetate butyrate, another polymer such as an epoxy resin, a polyester, an alkyd resin or an acrylic polyol, particularly a hydrolyzable silyl group-containing vinyl resin disclosed in, for instance, Japanese Unexamined Patent Publication No. 54-36395, and the like.
In a field that a curable resin is used in the state of a solution, particularly in a field of a coating, it is desired to prepare a high solid coating material which can be conformed to effluent regulations to solvents, for instance, prescribed in VOC Regulation provided in United States of America.
On the other hand, as to qualities to top coatings required in a market, particularly as to qualities of coatings for automobiles, it is desired to obtain an improved appearance due to intentions by user that goods of high grade are desired, it is desired to improve a scratch resistance, namely outside parts of an automobile are not scratched in a car washer, or it is desired to improve an acid rain resistance, derived from the environmental pollution.
As to melamine coatings which are generally used at the present time, in order to obtain a high solid coating, some efforts have been exerted. However, when a mixing ratio of a melamine resin component having a low viscosity is increased in the coating composition for obtaining a high solid coating, an acid resistance and a scratch resistance are further lowered. Also, an acid resistance and a scratch resistance of a regular solid coating are not necessarily attained to a satisfactory level.
An object of the present invention is to provide a curable resin which is improved in flexibility, solvent resistance, acid rain resistance and scratch resistance and is low in viscosity, and which is suitable for use of a blend with another resin.
A further object of the present invention is to provide a composition containing the above-mentioned resin which is improved in flexibility, solvent resistance, acid rain resistance and scratch resistance.
These and other objects of the present invention will become apparent from the description hereinafter.